Improvement in direct-acting engine valve-gear



n'itrd tatra parte (amm.

Letters Patent No. 92,648, [lated July 13, 1869; antetlatecl July 3,1869.

` IMPROVEMENT IN DIRECT-ACTING ENG-IE VALVE-GEAR.

The Schedule referred to in these Letters Patent and making part; of thesame.

To all whom it may concern Be it known that I, JOHN B. ROOT, of thecity, county, and State of New York, have invented a new and usefulImprovement in Valve-Gear of Direct- Acting Engines, of which thefollowing is a full, clear, and exact description, reference being hadto the accompanying drawing, forming part ot' this specification, inwhich Figure 1 represents a side elevation of an enginecylnder, with myimproved valve-gear applied thereto, an

Figure 2, a longitudinal section of the same, with the engine-piston asin position, or nearly so, for actuating or'starting the valves whichserve to control it.

Similar letters of reference indicate corresponding parts. Y

This, my improvement in valve-gear, is applicable to direct-actingengines oi' various kinds, includingvv steam-engines, pumps, andblowers; but it will suflice here to describe it as applied to adirect-acting steamengine.

My invention consists in the combination and arrangement ot' disk orpiston-valves, that control the ports at the opposite ends of thecylinder, said valves being connected, in a balanced manner, by arocking beam, having a shifting or movable fulcrum, operated by the'engine-piston, as it approaches the end of its respective strokes,through a sliding bai', shifting said fulcrum, and whereby thebalancing-character ot' the valves isdestroyed, by increasing thebeam-leverage of the one valve, as compared to the other, and so causingthe valves, under the pressure of steam or fluid, to rapidly changetheir positions, relatively to the ports, for the purpose of reversingthe stroke of the engine-piston.

Referring to the accompanying drawing- Ir represents the cylinder of adirect-acting engine, anc

B, the piston reciprocating therein.

G is a steam-chamber or space, supplied with steam from the boiler by apipe, a, and

D, an exhaust-chamber, having an outlet-pipe, b.

E E' are cylindrical valve-chambers, containing piston-valves G G',titiel to play in a` close but free manner therein.

These valve-chambers E E are connected, by upper` passages c e', withthe steam-space C, and by lower passages l el', with the exhaust-chamberD als'o, by ports or passages e e', with the cylinder A, at its oppositeends.

'Ihe valves G G' are, as it were, independent of each other, butconnected to work in unison, by means of rods ff, working throughstuing-boxes g y', and resting on, or otherwise being suitably attachedto the. opposite ends of a rocking beam, H, that works on a fulcrum, I.

This fulcrumit is necessary, should be of a movable or shiftingcharacter, in order that it may'be thrown destroys to opposite sidesy ofthe centre, orpoint which establishes a balanced action to the valves. 4

Thus, said fnlcrum may be a lcverworking in bear-- ings h h', and, whenthe valves are of eqlal area and weight, and beam of uniform shape, thesame may be disposed so that when standing vertical, or thereabout, thebeam H rests at its centre upon the fulcrum I.

The shaft i of said fulcrum carries a toe or arm, 7.',

arranged to gear with a sliding bar, J, that has con-` nected withit,.at opposite ends, rods m an', which project, through stung-boxes,into the intelgior of'the cylinder A, at its ends.

From this description, it will be seen that when the beam H rests at itscentre on the fnlcrnm I, the valves G G balance each other, the pressureof steam on their upper surfaces vbeing alike on both valves. ButY onsteam being admitted to throw the piston B to the right or left, andwhich may be done to start the engine, by sliding by hand, to the rightor left, the bar J, said piston, as it approaches the end of its stroke,strikes the one -rod m or on', and so throws the fulcrum I to theopposite side of the beam-centre, which the equilibrium of the valves,by increasing the beam-leverage of the one valve as compared to theother, so that the pressure of live steam on the valve having thelongest beam-leverage depresses said valve, and causes the oppositevalve-to be correspondingly raised. ports ee with Vthe steam andexhaust-chambers C and D, and so changes the direction in travel of thepiston. Alike rapid and automatic action of the valves occurs on thepiston reaching the other end of its stroke, by its striking the rod onor m', so as to shift the fulcrum I to the opposite side of thebeam-centre, and again reverse the position of the valves, relatively tothe ports, or passages controlled by them.

Thus, or by means of the shifting iulcrum, a single pair of valvessuffices, instead of two sets, in which the one is operated mechanicallyby the piston, and the other thrown by the steam, as the same isadmitted to them alternately, by the first pair or set of valves. In thepresent arrangement, the valves G G are thrown by the steam, but notuntil the fulcrum that secures their balance has been mechanicallyshifted by the engine.

`It is desirable that thevalve-cylinders E E shouldA be sufficientlyextended below the exhaust-passages d el to hold or contain a'certainamount-of spent steam when the valves are down, so as to act as acushion to said valves, and to secure to them an equilibrium, as regardspressure on their surfaces, and whereby they are made to play easier ontheshifting of the fulcrum. y

It also is desirable to make the throw of' the valvesl adjustable andvariable, as regards their action, in

point of time, relatively to the' piston. This may be done by making therods 'm m adjustable, by screwthread cut. on them, in or through theends of the This reverses the communication of the sliding bar J, sq asto cause said rods to project more or less within the cylinder, andthereby be struck earlier or later in the pistous stroke. VVbeu thusset, the rods m m may be secured by lock-nuts n n.

XVlxat is here claimed, and desired to be secured by Letters Patent, is

The arrangement and combination of the sliding bar J, lever I, and beamsH, with the valves G and G', for operating said valves by ton B,substantially as set forth Witnesses:

A. Las CLERC, A. KINNIER.

the travel of the pis- JOHN B. ROOT.

